Predictability of Proximal Enamel Thickness Assessment using Intraoral Periapical Radiographs: A Cross-sectional Study

Abstract

Introduction: Measurements of tooth crown dimensions and enamel thickness are useful guides for interproximal stripping procedures aimed at creating space. In borderline non extraction orthodontic treatment cases, interproximal stripping is performed to gain space. Intraoral periapical radiographs and bitewing radiographs are commonly used to determine Proximal Enamel Thickness (PET). Aim: To determine the predictability of using IOPA-based PET measurements for assessing real/anatomic PET. Materials and Methods: This was a single-centre, crosssectional study conducted at Saveetha Dental College and Hospital, Chennai, Tamil Nadu, India, between March 2022 and April 2022. Digital Intraoral Periapical Radiographs (IOPAs) of 40 premolar teeth with intact crown structures were obtained using the paralleling technique. The PET of both the mesial and distal sides of the same teeth was measured using Carestream Imaging software. Subsequently, the extracted teeth were sectioned and examined under a Stereomicroscope (SM), and PET measurements of the mesial and distal surfaces were obtained along the heights of contour using ImageJ analysis software. Pearson’s correlation, along with linear and polynomial regression analyses, was performed using International Business Machines (IBM) Statistical Package for Social Sciences (SPSS) software. Results: A low but significant positive correlation between the PET of the sectioned teeth and the PET measured from IOPAs was observed (p=0.002, R=0.55). A significant difference in PET between the two methods for both sides was noted (p<0.05). The mean distal enamel thickness was significantly greater than the mean mesial enamel thickness for both the IOPA and SM methods (p<0.05). A polynomial regression equation, Y=2.084- 1.234X+0.318X3 , was established to predict PET of the sectioned teeth (Y) based on PET measured from IOPAs (X). Conclusion: The present study establishes a correlation between the true PET of teeth measured using cut-sections and PET measured from IOPAs, which are readily available in clinical practice. A correlation coefficient was determined, and PET can be predicted using IOPAs, although not with absolute accuracy. Distal PET was found to be higher than mesial PET, with no significant difference in enamel thickness between the two sides.